Remove call to miInitializeBackingStore()
Remove call to miInitializeBackingStore()

Recent versions of the X server no longer provide this function, which
has been obsolete for over 2 years now.

Signed-off-by: Thierry Reding <b75a4d02013b0e68ae2c6bb0dcfd4b7bec282dc9@avionic-design.de>
Reviewed-by: Alex Deucher <08dc22c6156113f2deff178e35e3ed9b24d6af9e@amd.com>
Signed-off-by: Dave Airlie <f2295d84e358395675bc8031be58672073ae065e@redhat.com>

patjak/xf86-video-gma500,patjak/xf86-video-gma500,wzyy2/xf86-video-modesetting,wzyy2/xf86-video-modesetting